senting not only ecologically but specifically the climatic societies 

 of regions far to the north. 



3. This striking ecological and specific similarity of the floras 

 of high mountains, the Arctics, sphagnum bogs and borders of 

 cold ponds, is probably caused by a physiological identity of the 

 various habitats, a physiologically dry soil, a xerophytic soil. 

 Such habitats are characterized by a high transpiration-ratio due 

 to an identical cause, minimized absorption, probably determined, 

 in part at least, by the retardative effect of low temperature. 



4. The Krummhols of the "tableland," "saddle" and upper 

 slopes is a depauperate mesophytic forest determined by the high 

 precipitation, its happy distribution, and abundlant retention. 



5. There is no true climatic timber-line upon Ktaadn. The 

 demarkation between Alpine-Tundra and Krummhols forest 

 upon the higher slopes is merely edaphic. At the base of the 

 precipitous lower slopes the so-called "timber-line" is in reality 

 an avalanche line. 



6. The length of the life history of a pond determines its 

 temporary climax; if short the natural meadow, if long the 

 sphagnum bog is the result. 



7. Whatever the pioneer stage and the order and rate of suc- 

 cession, all the plant societies are progressing toward a common 

 end, the Pic ea- Abies combination, the climax mesophytic forest 

 of the region. 



8. The glacial relict theory may be extended to account for 

 the Arctic affinity of the sphagnum bog flora of extra montane 

 pounds ; while in local and valley glaciation may be sought the 

 origin of the Arctic-Alpine flora which borders the shores of 

 ponds and forms the sphagnum bogs within the Mt. Ktaadn 

 region. 



BIBLIOGRAPHY. 

 Aubert, A. B. Diatomees du* Mount Ktaadn. Le Diatomiste 



21 211. 1895. 



Bailey, J. W. Account of an Excursion to Mt. Katahdin in 



Maine. Am. Jour. Sci. 32: 20-34. 1837. 

 Briggs, F. P. Plants Collected at Mt. Ktaadn, Me. Torr. Bui. 



J P- 333-336. 1892. 



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